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Deficiency of macrophage migration inhibitory factor attenuates tau hyperphosphorylation in mouse models of Alzheimer's disease.

Li SQ, Yu Y, Han JZ, Wang D, Liu J, Qian F, Fan GH, Bucala R, Ye RD - J Neuroinflammation (2015)

Bottom Line: CM from high glucose-treated WT astrocytes increased tau hyperphosphorylation in cultured primary neurons, an effect absent from Mif (-/-) astrocytes and WT astrocytes treated with the MIF inhibitor ISO-1.ISO-1 had no direct effect on tau phosphorylation in cultured primary neurons.Inhibition of MIF and MIF-induced astrocyte activation may be useful in AD prevention and therapy.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China. shuqinliky@163.com.

ABSTRACT

Background: Pathological features of Alzheimer's disease (AD) include aggregation of amyloid beta (Aβ) and tau protein. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, has been implicated in the toxicity of aggregated Aβ. It remains unclear whether MIF affects hyperphosphorylation and aggregation of tau.

Methods: The effects of MIF deficiency in tau hyperphosphorylation were examined in Mif (-/-) mice receiving intracerebroventricular (ICV) injection of streptozotocin (STZ) and in APP/PS1 transgenic mice mated with Mif (-/-) mice. MIF expression and astrocyte activation were evaluated in ICV-STZ mice using immunofluorescence staining. Cultured primary astrocytes were treated with high glucose to mimic STZ function in vitro, and the condition medium (CM) was collected. The level of tau hyperphosphorylation in neurons treated with the astrocyte CM was determined using Western blotting.

Results: MIF deficiency attenuated tau hyperphosphorylation in mice. ICV injection of STZ increased astrocyte activation and MIF expression in the hippocampus. MIF deficiency attenuated astrocyte activation in ICV-STZ mice. CM from high glucose-treated WT astrocytes increased tau hyperphosphorylation in cultured primary neurons, an effect absent from Mif (-/-) astrocytes and WT astrocytes treated with the MIF inhibitor ISO-1. ISO-1 had no direct effect on tau phosphorylation in cultured primary neurons.

Conclusions: These results suggest that MIF deficiency is associated with reduced astrocyte activation and tau hyperphosphorylation in the mouse AD models tested. Inhibition of MIF and MIF-induced astrocyte activation may be useful in AD prevention and therapy.

No MeSH data available.


Related in: MedlinePlus

Upregulation of MIF in ICV-STZ mice and colocalization with GFAP in the hippocampus. a Serial sections of WT mouse brain were stained for MIF protein using a rabbit anti-MIF polyclonal antibody and Alexa Fluor 488-conjugated anti-rabbit IgG (green fluorescence). The sections were subsequently stained for GFAP using a monoclonal anti-GFAP Cy3TM antibody (red fluorescence). Nuclei were stained with DAPI (blue). Images with combined fluorescent channels are shown at ×200 (scale bar in the upper left panel 75 μm). Selected areas are enlarged by 10 times and shown as combined as well as individual fluorescence stains. Quantification of the MIF (b) and GFAP (c) fluorescence was shown after normalization of the green (MIF) and red (GFAP) fluorescence against the blue fluorescence (nuclei). Data shown are means ± SEM based on multiple experiments (n = 3). *p < 0.05, **p < 0.01 compared with WT mice receiving saline
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Fig4: Upregulation of MIF in ICV-STZ mice and colocalization with GFAP in the hippocampus. a Serial sections of WT mouse brain were stained for MIF protein using a rabbit anti-MIF polyclonal antibody and Alexa Fluor 488-conjugated anti-rabbit IgG (green fluorescence). The sections were subsequently stained for GFAP using a monoclonal anti-GFAP Cy3TM antibody (red fluorescence). Nuclei were stained with DAPI (blue). Images with combined fluorescent channels are shown at ×200 (scale bar in the upper left panel 75 μm). Selected areas are enlarged by 10 times and shown as combined as well as individual fluorescence stains. Quantification of the MIF (b) and GFAP (c) fluorescence was shown after normalization of the green (MIF) and red (GFAP) fluorescence against the blue fluorescence (nuclei). Data shown are means ± SEM based on multiple experiments (n = 3). *p < 0.05, **p < 0.01 compared with WT mice receiving saline

Mentions: MIF is a proinflammatory cytokine that plays an important role in inflammatory response by stimulating glial cells. It is postulated that MIF-activated glial cells may contribute to tau phosphorylation in neurons. To test this possibility, we first examined the expression of MIF in WT mice that received ICV injection of saline or STZ. Immunofluorescence staining of serial slices from WT mouse brain with antibodies against MIF (green fluorescence) identified a significant upregulation of MIF in CA and DG areas of hippocampus in ICV-STZ mice compared to mice receiving saline (Fig. 4a, b). Moreover, it is evident that the increased MIF colocalized with neurons based on the staining pattern (Fig. 4a), consistent with a previous study [13]. To investigate the activation of astrocytes and their distribution, we stained frozen slices of brain tissue with CY3TM conjugated mouse monoclonal anti-glial fibrillary acidic protein (GFAP; red fluorescence). The expression of GFAP, a protein abundant in activated astrocytes, was increased in ICV-STZ mice. Double immunofluorescence staining showed an increase in MIF colocalization with activated astrocytes in the brain of ICV-STZ mice (Fig. 4a), which showed increased GFAP expression (Fig. 4a, c). These results suggest that ICV injection of STZ induce the expression of MIF and the activation of astrocytes.Fig. 4


Deficiency of macrophage migration inhibitory factor attenuates tau hyperphosphorylation in mouse models of Alzheimer's disease.

Li SQ, Yu Y, Han JZ, Wang D, Liu J, Qian F, Fan GH, Bucala R, Ye RD - J Neuroinflammation (2015)

Upregulation of MIF in ICV-STZ mice and colocalization with GFAP in the hippocampus. a Serial sections of WT mouse brain were stained for MIF protein using a rabbit anti-MIF polyclonal antibody and Alexa Fluor 488-conjugated anti-rabbit IgG (green fluorescence). The sections were subsequently stained for GFAP using a monoclonal anti-GFAP Cy3TM antibody (red fluorescence). Nuclei were stained with DAPI (blue). Images with combined fluorescent channels are shown at ×200 (scale bar in the upper left panel 75 μm). Selected areas are enlarged by 10 times and shown as combined as well as individual fluorescence stains. Quantification of the MIF (b) and GFAP (c) fluorescence was shown after normalization of the green (MIF) and red (GFAP) fluorescence against the blue fluorescence (nuclei). Data shown are means ± SEM based on multiple experiments (n = 3). *p < 0.05, **p < 0.01 compared with WT mice receiving saline
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4574615&req=5

Fig4: Upregulation of MIF in ICV-STZ mice and colocalization with GFAP in the hippocampus. a Serial sections of WT mouse brain were stained for MIF protein using a rabbit anti-MIF polyclonal antibody and Alexa Fluor 488-conjugated anti-rabbit IgG (green fluorescence). The sections were subsequently stained for GFAP using a monoclonal anti-GFAP Cy3TM antibody (red fluorescence). Nuclei were stained with DAPI (blue). Images with combined fluorescent channels are shown at ×200 (scale bar in the upper left panel 75 μm). Selected areas are enlarged by 10 times and shown as combined as well as individual fluorescence stains. Quantification of the MIF (b) and GFAP (c) fluorescence was shown after normalization of the green (MIF) and red (GFAP) fluorescence against the blue fluorescence (nuclei). Data shown are means ± SEM based on multiple experiments (n = 3). *p < 0.05, **p < 0.01 compared with WT mice receiving saline
Mentions: MIF is a proinflammatory cytokine that plays an important role in inflammatory response by stimulating glial cells. It is postulated that MIF-activated glial cells may contribute to tau phosphorylation in neurons. To test this possibility, we first examined the expression of MIF in WT mice that received ICV injection of saline or STZ. Immunofluorescence staining of serial slices from WT mouse brain with antibodies against MIF (green fluorescence) identified a significant upregulation of MIF in CA and DG areas of hippocampus in ICV-STZ mice compared to mice receiving saline (Fig. 4a, b). Moreover, it is evident that the increased MIF colocalized with neurons based on the staining pattern (Fig. 4a), consistent with a previous study [13]. To investigate the activation of astrocytes and their distribution, we stained frozen slices of brain tissue with CY3TM conjugated mouse monoclonal anti-glial fibrillary acidic protein (GFAP; red fluorescence). The expression of GFAP, a protein abundant in activated astrocytes, was increased in ICV-STZ mice. Double immunofluorescence staining showed an increase in MIF colocalization with activated astrocytes in the brain of ICV-STZ mice (Fig. 4a), which showed increased GFAP expression (Fig. 4a, c). These results suggest that ICV injection of STZ induce the expression of MIF and the activation of astrocytes.Fig. 4

Bottom Line: CM from high glucose-treated WT astrocytes increased tau hyperphosphorylation in cultured primary neurons, an effect absent from Mif (-/-) astrocytes and WT astrocytes treated with the MIF inhibitor ISO-1.ISO-1 had no direct effect on tau phosphorylation in cultured primary neurons.Inhibition of MIF and MIF-induced astrocyte activation may be useful in AD prevention and therapy.

View Article: PubMed Central - PubMed

Affiliation: School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China. shuqinliky@163.com.

ABSTRACT

Background: Pathological features of Alzheimer's disease (AD) include aggregation of amyloid beta (Aβ) and tau protein. Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, has been implicated in the toxicity of aggregated Aβ. It remains unclear whether MIF affects hyperphosphorylation and aggregation of tau.

Methods: The effects of MIF deficiency in tau hyperphosphorylation were examined in Mif (-/-) mice receiving intracerebroventricular (ICV) injection of streptozotocin (STZ) and in APP/PS1 transgenic mice mated with Mif (-/-) mice. MIF expression and astrocyte activation were evaluated in ICV-STZ mice using immunofluorescence staining. Cultured primary astrocytes were treated with high glucose to mimic STZ function in vitro, and the condition medium (CM) was collected. The level of tau hyperphosphorylation in neurons treated with the astrocyte CM was determined using Western blotting.

Results: MIF deficiency attenuated tau hyperphosphorylation in mice. ICV injection of STZ increased astrocyte activation and MIF expression in the hippocampus. MIF deficiency attenuated astrocyte activation in ICV-STZ mice. CM from high glucose-treated WT astrocytes increased tau hyperphosphorylation in cultured primary neurons, an effect absent from Mif (-/-) astrocytes and WT astrocytes treated with the MIF inhibitor ISO-1. ISO-1 had no direct effect on tau phosphorylation in cultured primary neurons.

Conclusions: These results suggest that MIF deficiency is associated with reduced astrocyte activation and tau hyperphosphorylation in the mouse AD models tested. Inhibition of MIF and MIF-induced astrocyte activation may be useful in AD prevention and therapy.

No MeSH data available.


Related in: MedlinePlus